11 year old Carrier 58yav stumping the technician and me - yet another flame rollout

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11 year old Carrier 58yav stumping the technician and me - yet another flame rollout

After trying to troubleshoot, reading this forum, tand having a technician out, the problem can't be solved and hoping for help here.

Equipment: carrier 58yav 110btu installed 2001. Installed in house with clay chimney flue shared with water heater. Unit installed with carrier chimney adapter designed for use in clay chimney. Chimney adapter contains standard bvss switch correctly installed in series with dss flame rollout switch and pressure switch. Installed McLean, Virginia. Clean filter, unobstructed air ingress/egress, clean single speed blower seems working fine.
History- We bought house 2005- unit had no problems until about 2009
In 2009, we had one DSS flame rollout reset in the season. Igniter also replaced this year
2010, 2011 - 2 or 3 roll outs switch reset each year
2012- last few weeks, persistent flame rollout reset after about 10 minutes of running with heat/burners fired.
2012- pressure switch replaced with factory part
2012- this week, replaced dss flame rollout switch, correct factory part

Prior to having technician out I had chimney inspected (also did myself), cleaned inside of unit carefully, measured rpm in inducer motor speed to be spec at 3400,inspected inducer motor internal fan through flue exit at top of unit and is very clean, and burners look clean. Very little to no rust.

Tech came out and measured temperature at dss rollout switch. He determined it was getting too hot. He didn't understand the chimney adapter operation entirely, but he noted that when he temporarily restricted the air entering the chimney adapter, the temperature across the rollout switch decreased. He called his supervisor and advised that "you need a liner for the chimney" but they also agreed that the chimney was in specification for the chimney adapter. I also asked why we would need to do this given that the unit worked ok for years. The tech then inspected the heat exchanger from up above by looking down from the ac coils installed above unit. He felt the heat exchanger looked very good. Neither he nor I could see obvious flame rollout in operation. As last effort, tech adjusted gas pressure valve to try to reduce gas pressure. I think he said that the air coming from the unit was a little too hot as well. This did not solve the problem. Technician left telling me to get a liner and he would remove chimney adapter. Final observation is that the chimney flue vent pipes that run for about 6 feet and 2 elbow turns should be double walled and now it is only single walled. Unclear if that is correlated to issue and if so, why it would appear as a problem now 11 years post installation.

I have run out of options and greatly appreciate any help you can provide

1st
If venting anywhere between furnace & chimney is single wall pipe- it is NOT approved. Instructions say type B, no exceptions. Someone didn't follow instructions. Makes me wonder about the rest of the install.
Venting a 78 AFUE induced furnace into any unlined chimney is something I would have never done. I don't care what they call that adaptor, not the correct way to vent in my book. & I've been doing this for 42 years.
Lots of unknowns.
Area of chimney
Does chimney terminate below roof peak?
Size of connector at chimney
Size of vent piping for furnace & water heater
Do furnace & water heater share vent to chimney or are they run separately?
Pitch
Total horizontal length
Winter design temps
Combustion air

This is not a DIY project. You sound like you are trying to diagnose on your own. I have suggestions & install instructions for both furnace & chimney kit but could be dangerous for a HO to attempt repairs themselves. You need to call out a real pro & don't be so dismissing if they tell you to line the chimney. I wouldn't care how long it's been working that way.

Thanks for your help, this is what I was looking for. I did call a tech and have another coming. My purpose here is to understand the issues as not all hvac technicians are as experience or honest as yourself. I agree on b vent, raises questions. Also question if correct pitch etc. Tech did not take out a calculator or level but felt the current length and sizing was ok but at upper limit. I gave him the carrier chimney adapter manual. If he had said hey, it isn't a good run I would have let you know of that. He measured the diameter if all pipes with a dollar bill as hia guide and i showed him clay opening. The chimney is about 8 feet above roof line, 2 story house normal height stories. House is 1955 build brick and block. Chimney is on outside wall. As I had noted gas water heater is venting to same flue. My feeling is that we will line it anyway though I can say the clay flue is clean and looks perfect. So lets way we reline, doesn't this still look like a cracked heat exchanger? I am asking NOT because I would do it myself but to gauge if the next tech says replace it, heat exchanger, then I get some input from you guys that this is likely.

Just for info sake-
DSS switch is a spill switch or a high temp limit switch. Roll out switches will be placed around burner area.
Anytime that switch opens- it's telling you you have venting issues. Vent is obstructed, or not drawing properly. Even if HX was cracked- may not affect any of the spill or temp switches.
A good tech can inspect the HX. I'd also install a CO detector in the home. Don't buy cheap! Your life depends on it.
You need a thorough combustion analysis performed.
Many HO's fall into a mentality of "Well, it worked like that for years". If you read your install instructions for the kit- they come pretty close to recommending lining the chimney anyway.
If I was there- 1st words out of my mouth would be to line the chimney or find a new route for a B vent.

Thank you, this is definitely not about being cheap, it is about understanding as I don't cut corners on this but need info as getting a quality job done is difficult. Also I have a CO sensor in the utility room and around the house. In fact the tech set that off when he removed the flue for testing. Your perspective that a liner is a given and the next best step to eliminate variables and assure safety is valuable to me and again I appreciate that help. I am an engineer and don't accept poor past operating anything as an excuse for continued operation. My point was to understand why carrier would spec this out and why,if in spec, it would need replacement. I think your perspective if I understand it correctly is that the chimney adapter setup introduced too many variables and risk and you think it should be eliminated as a variable and safety risk. I will say that while carrier sells this product I have seen very little online written about it which has me wondering how often it has been put into use.

Thank you, this is definitely not about being cheap, it is about understanding as I don't cut corners on this but need info as getting a quality job done is difficult. Also I have a CO sensor in the utility room and around the house. In fact the tech set that off when he removed the flue for testing. Your perspective that a liner is a given and the next best step to eliminate variables and assure safety is valuable to me and again I appreciate that help. I am an engineer and don't accept poor past operating anything as an excuse for continued operation. My point was to understand why carrier would spec this out and why,if in spec, it would need replacement. I think your perspective if I understand it correctly is that the chimney adapter setup introduced too many variables and risk and you think it should be eliminated as a variable and safety risk. I will say that while carrier sells this product I have seen very little online written about it which has me wondering how often it has been put into use.

You have CO sensors around the house, they don't go off when the furnace is running so I doubt you are having HX issues. It sounds like your unconventional flue is the problem.

"When the people find they can vote themselves money,that will herald the end of the republic" - Benjamin Franklin

"Government is not reason, it is not eloquence, it is force;like fire, a troublesome servant and a fearful master. Never for a moment should it be left to irresponsible action"- George Washington

You have CO sensors around the house, they don't go off when the furnace is running so I doubt you are having HX issues. It sounds like your unconventional flue is the problem.

Unless you are using low level co detectors then they won't go off until seconds before the co puts you to sleep for good. The co detectors sold in box stores are pretty much good for nothing. Something like this http://www.aeromedix.com/CO_Experts_...odel_2010.html would actually alert you of a problem.

CO and next steps

Thanks. I have them around the house and they have gone off when car was running in garage once (dumb move, a little too long) they are higher end units. Some came with Simon xt alarm system and others.

I am having a closer look at the chimney again today myself and have hvac tech and chimney people coming tomorrow. I had ducts intake and out professionally cleaned last year and should all be ok and unobstructed, will take one more peak. Using my inspection camera, hx looked ok but I will have another look with tech. Btw not sure if I used right terms, the dss switch is what is tripping with code 31. It is actually tripping not just computer reporting 31. I also called this the rollover switch not sure if that is right term. It measures temperature near top of furnace flue output.
I will update thread with final resolution or further questions and again thanks for everyone's help.

Have your tech do a combustion analysis of the flue gas. CO being high enough to set off the detectors when the flue was off is a huge concern. Guessing you are well above the 100ppm limit in the flue.

Flue off and venting into room when tech tested

Originally Posted by martyinlincoln

Have your tech do a combustion analysis of the flue gas. CO being high enough to set off the detectors when the flue was off is a huge concern. Guessing you are well above the 100ppm limit in the flue.

Thanks, will do. Want to make sure I understand and was clear in the info I provided, I may not have been clear. The tech entirely removed the vent from the unit meaning that the unit was venting directly into the room and not the chimney. The room is big enough for furnace, ac unit, water heater, washer and dryer (electric) and 2 shelves. Door was open. The CO detector in the same room (it is on wall across from furnace) went off. So given that clarification, would you still say the CO detector should have not gone off?

Btw another professional chimney inspector comes tomorrow. Ahead of that I inspected again the clay pipe in the chimney leading horizontally from the room and making a quick elbow right then another quick elbow up the chimney. This is hard to inspect. I used a whistler inspection camera with a wireless video (Costco sells this package) with a 3 foot extension, 6 feet total, and put the camera gun on a pole which I could do because the videos screen is wireless. I recorded the video. The elbow area and pipe is extremely clean, clear, and good shape. Them lay liner tile on chimney section also very clean. Will see what second chimney inspector says tomorrow.

please read the thread - that is not what was said

What I said was he took the venting off and the CO detector DID go-off. This is what I wrote above.

Another technician came-out today. Here is what he stated. He did not have the equipment to do a combustion analysis.

1- The chimney adapter is common in Virginia where we live. The brick and block houses with clay lined chimneys will have these. However, I do agree with HVAC technicians in the thread that argue for lining the chimney. It definitely reduces risk and unknowns. The chimney people are coming-out. They stated that they do not normally recommend or perform lining on chimneys flues in our area if the clay is in good condition. Again not discounting any good points here, I'm just letting you know what these people are saying.

2- The unit looked good to him. No issues with HX.

3- He pulled the inducer motor. It looked good. As I noted above in my thread it had measured 3400 RPM. Fan on inducer motor was clean.

4- He reinstalled the inducer motor. This seemed to change behavior of the unit. We now had correct pressure (pretty much none) in front of the DSS switch and the chimney adapter was no longer sucking air. System ran longest since this season, 30 minutes, and no resets yet. We are awaiting the chimney folks today.'

His conclusions: Either odd/strange flaky inducer motor needs replacement or chimney has issue. While 30 minutes is not an absolute test, I'm beginning to think the inducer motor is the cause.

Chimney people are coming in about an hour. So that's where we are at. Thanks to everyone for their help thus far.